YM2000 3 point lift

[crawfish-HT]

I'm working on a YM2000 with a bush hog and a Bulldog front end loader. The 3 point lift will raise the bush hog for about 3-5 minutes after the tractor is started, then it get progressively "weaker" and gets to the point that it wont lift it at all. The front end loader works fine all the time, even when the 3 point won't lift the bush hog. Does this indicate that the 3 point control is bad? Thanks.

 

[winston-HT]

will the lift hold up when you kill the tractor or just how fast will it leak down? Is your loader plumbed with power beyond?

 

[crawfish-HT]

The lift won't hold when you kill the tractor. Heck, it won't even hold when the tractor is running. After it starts getting "weak" I can put the control in the raise position and the bush hog won't move. With the engine running if I physically lift the bush hog, it will raise, but as soon as I quit lifting, it starts lowering.

Not sure about "power beyond". My best guess is that the loader is plumbed in series with the rest of the hydraulic system. The line from the hydraulic pump was cut, and from the pump it is plumbed into the loader control valve, then out of the loader control valve and back into the line.

 

[winston-HT]

Your plumbing would seem to be without power beyond so that would rule out your loader valve I think. My first suspicion would be the lift piston o-ring and/or backup ring is shot but it could be a leaking relief valve or control valve. #19 and 20 here. http://www.hoyetractor.com/CTGY/2000HYDLIFT.htm

 

[crawfish-HT]

If I raise the 3 point, close the lockout valve, and the 3 point stays up, will that narrow down the problem?

I've read on this site that you shouldn't close the lockout valve with the engine running as it can/will cause damage to the hyd pump. Does the front end loader control valve have a built in pressure relief? If it does, and the front end loader control valve is plumbed in series, would it's pressure relief valve prevent the hyd pump from damage if the lockout valve is closed with the engine running?

 

[winston-HT]

<QUOTE author="crawfish"><s>

</s>If I raise the 3 point, close the lockout valve, and the 3 point stays up, will that narrow down the problem?

Yes. Close with engine off.

I've read on this site that you shouldn't close the lockout valve with the engine running as it can/will cause damage to the hyd pump. Does the front end loader control valve have a built in pressure relief? If it does, and the front end loader control valve is plumbed in series, would it's pressure relief valve prevent the hyd pump from damage if the lockout valve is closed with the engine running?<e>

/e></QUOTE>

No, the loader control valve relief valve will not protect the 3 point. It only protects the loader valve and cylinders. The fluids only exit is through the 3 point when plumbed without power beyond. The only tank return is through the 3 point.

 

[crawfish-HT]

There is a hydraulic line that is plumbed from the loader control valve into the side of oil fill/dipstick boss. What would it's purpose be other than a dump for the loader pressure relief?

If you operate the loader with the 3 point raised, the 3 point will lower.

 

[winston-HT]

<QUOTE author="crawfish"><s>

</s>There is a hydraulic line that is plumbed from the loader control valve into the side of oil fill/dipstick boss. What would it's purpose be other than a dump for the loader pressure relief?

That line is tank return line, so you do have power beyond. When you use your loader control valve the fluid goes through that line, when not using the loader the fluid goes through the line going to the 3 point control valve.

If you operate the loader with the 3 point raised, the 3 point will lower.<e>

/e></QUOTE>

Evidence of bad piston seal, control valve, etc. because you are taking the constant pressure off the three point when you operate the loader.

 

[alan-HT]

Assuming you've had the tractor for a time during which the lift was normal, I'd agree.